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SHIP-BORNE PLAGUE.
1218
SHIP-BORNE PLAGUE. THE annual report of the chief medical ofticer of the of Health for 1919-20 contains, amongst other reports which we have already noticed. a valuable contribution on the subject of ship-borne plague, by Dr. R. J..Reece, one of the senior medical officers of the Ministry. It comprises a summary of the more important facts relating to the circumstances associated with the occurrence of the disease on board ships arriving at the ports of England and Wales during the last 25 years by one whose complete experience enables him to write authoritatively on the subject. During recent years the number of plague-infected vessels coming into British ports has increased. This, in Dr. Reece’s view, may be attributed to conditions brought about by the war, which have resulted in large quantities of food-stuffs and other cargoes being stored for long periods awaiting transport at certain ports abroad, such as Bombay, Alexandria, and the South American ports. Before shipment this merchandise is liable to become infested with rats, with the result that the number of these rodents found on board cargo-carrying vessels has materially increased since the signing of the armistied. When a vessel arrives at one of our ports and declares that she is an " infected " or " suspected " vessel, or when it is known that she has come from a plagueinfected port, prompt measures are taken at the port of arrival to prevent the introduction of the disease into the country.
Ministry
Difficulties of Recognition of Plague. A study of the many examples given by Dr. Reece shows that this preliminary information is not always forthcoming, and consequently the task of a port medical officer of health is at times far from easy. In the first place, it has to be remembered that the number of merchant vessels carrying a ship’s surgeon is relatively few and that the recognition of plague by an untrained observer is often difficult. The bubonic type is generally correctly diagnosed because it is widely known that this form is accompanied by glandular swellings. In the septicaemic and pneumonic forms the virulence of the disease and the rapidity of the fatal issue often mask the diagnosis. On board ship these forms may be confused with malignant malaria, influenza, or typhus fever, and thus it not infrequently happens that those on board a plague-infected vessel have no idea of the true nature of the malady. In the second place, a vessel coming from a port where no plague is known to exist may yet have plague-infected rats on board. It appears probable that plague may exist undiscovered among rats on board a vessel for many months. In the case of the s.s. Highland Prince, for example, the infection was probably taken on board the vessel in June and did not become manifest until the first days of October. - method of Infection on Boa1’d Ship. It is common knowledge that the modern ship is generally built in water-tight compartments, at any rate below the water-line, often with no direct communication between holds; to get from one hold to another a rat would have to come to the upper decks. Plague infection may therefore be entirely limited to one hold, rats therein dying of the disease whilst those in other holds remain healthy. In such circumstances should all the rats and rat fleas die, there will be no spread of infection to man when the holds ara opened for the purpose of discharging the cargo. On the other hand, fleas leave the body of a rat when it dies, and it is therefore a dangerous procedure for a man to enter the hold of a ship in which rats have died. Again, much depends upon the cargo carried ; when a ship is empty or when the cargo does not afford food for rats they will make their way, if possible, to the places on the ship where the food of the crew is stored or prepared. Thus the first human case on board a vessel is often some member of the crew whose duties take him into the food store. The storekeeper or the saloon steward who carries the food from the galley to the
saloon is specially liable to infection, and the steward may in turn infect the captain and other officers upon whom he attends. It is therefore of importance that all food stores on board ship should be rendered ratproof. It appears probable that rats often gain access to ships by being carried on board with the cargo. They have sometimes been found in bales, bags, barrels, and crates containing a variety of different goods, such as grain, fruit, and yegetables, particularly when a cargo intended for a vessel has been left undisturbed for some time in dock warehouses. Before shipment such cargo should be carefully looked over. Above all, every means should be employed to prevent rats at a plague-infected port gaining access to a vessel which is to carry grain or other cargo to a distant country. It is probable that this precaution has not always been observed in the past.
TI’anspo1’t of Rats. As indicating the extent to which rats from
are
conveyed
to another through the agency of shipping Dr. Reece’s remarks on the change of the species of rats found at the English ports are very interesting. A hundred and fifty years ago the rat of this country was the Mus rattus, the black rat, or old English rat. When the brown rat, 31,us decumanus, came to Britain it practically exterminated the old English rat, and a few years ago it was hardly possible to obtain a specimen of the black rat. In recent years the rat population of this country has undergone a further change owing to the reintroduction from abroad of the black rat and the appearance of a third species, also black, known as the Mus alexandrinus. From returns received by the Ministry of Health it would appear that these two rats are increasing in number at certain ports. The number of brown rats destroyed at London and Cardiff far exceeds the number of black rats, whereas at Liverpool and Hull the two black rats predominate. The presence among ships’ rats of the species most prone to acquire, carry, and transmit the infection of plague is somewhat disquieting and demonstrates the desirability of destroying these rodents at the point at which this process may most effectively be carried out-namely, on board ship immediately after discharge of the cargo. one
country
Plagtw Prevention at Liverpool. The annual report for 1919 of the medical officer of health to the Port Sanitary Authority of Liverpool contains, in the section devoted to rats and plague, tables showing that over 20,000 rats were caught on ships and quays by the authority’s rat-catchers during the year, in addition to 50,000 disposed of by various shipping firms employing their own means of deratisaAn example of the new duties imposed on tion. port sanitary authorities by recent legislation is the Rats and Mice Destruction Act, 1919, which applies to a vessel as though it were land ; the master of a vessel is deemed to be the occupier thereof, thus becoming responsible for taking reasonable and practical steps to rid his property of rats and mice. The world-wide distribution of plague was maintained during the year, but one case only was landed at Liverpool out of a ship which had sailed from Bombay. In the port of Liverpool 310 rats were examined bacteriologically, and 20 of this number were found to be plague-infected; most of the latter could be traced to a single vessel. The following precautions were adopted. The vessel was breasted 6 feet off the quay, rat-guards were placed on all mooring-ropes, gangways were whitewashed and hoisted when not in use; extra labour was engaged, the cargo was searched for rats, the vessel also searched before, during, and after discharge of cargo ; the names and addresses of the crew were obtained and the men visited ; any dock labourer or carpenter absent from work on account of sickness was also visited; rat-catchers were kept continually at work on ship and quays; the matchboard lining and flooring of the lazaret were stripped and burnt, and the apartment thoroughly sprayed with kerosene; dead rats when found were immediately disinfected, and the whole vessel when empty was subjected to complete and simultaneous disinfection.
-
,
SHIP-BORNE PLAGUE. THE annual report of the chief medical ofticer of the of Health for 1919-20 contains, amongst other reports which we have already noticed. a valuable contribution on the subject of ship-borne plague, by Dr. R. J..Reece, one of the senior medical officers of the Ministry. It comprises a summary of the more important facts relating to the circumstances associated with the occurrence of the disease on board ships arriving at the ports of England and Wales during the last 25 years by one whose complete experience enables him to write authoritatively on the subject. During recent years the number of plague-infected vessels coming into British ports has increased. This, in Dr. Reece’s view, may be attributed to conditions brought about by the war, which have resulted in large quantities of food-stuffs and other cargoes being stored for long periods awaiting transport at certain ports abroad, such as Bombay, Alexandria, and the South American ports. Before shipment this merchandise is liable to become infested with rats, with the result that the number of these rodents found on board cargo-carrying vessels has materially increased since the signing of the armistied. When a vessel arrives at one of our ports and declares that she is an " infected " or " suspected " vessel, or when it is known that she has come from a plagueinfected port, prompt measures are taken at the port of arrival to prevent the introduction of the disease into the country.
Ministry
Difficulties of Recognition of Plague. A study of the many examples given by Dr. Reece shows that this preliminary information is not always forthcoming, and consequently the task of a port medical officer of health is at times far from easy. In the first place, it has to be remembered that the number of merchant vessels carrying a ship’s surgeon is relatively few and that the recognition of plague by an untrained observer is often difficult. The bubonic type is generally correctly diagnosed because it is widely known that this form is accompanied by glandular swellings. In the septicaemic and pneumonic forms the virulence of the disease and the rapidity of the fatal issue often mask the diagnosis. On board ship these forms may be confused with malignant malaria, influenza, or typhus fever, and thus it not infrequently happens that those on board a plague-infected vessel have no idea of the true nature of the malady. In the second place, a vessel coming from a port where no plague is known to exist may yet have plague-infected rats on board. It appears probable that plague may exist undiscovered among rats on board a vessel for many months. In the case of the s.s. Highland Prince, for example, the infection was probably taken on board the vessel in June and did not become manifest until the first days of October. - method of Infection on Boa1’d Ship. It is common knowledge that the modern ship is generally built in water-tight compartments, at any rate below the water-line, often with no direct communication between holds; to get from one hold to another a rat would have to come to the upper decks. Plague infection may therefore be entirely limited to one hold, rats therein dying of the disease whilst those in other holds remain healthy. In such circumstances should all the rats and rat fleas die, there will be no spread of infection to man when the holds ara opened for the purpose of discharging the cargo. On the other hand, fleas leave the body of a rat when it dies, and it is therefore a dangerous procedure for a man to enter the hold of a ship in which rats have died. Again, much depends upon the cargo carried ; when a ship is empty or when the cargo does not afford food for rats they will make their way, if possible, to the places on the ship where the food of the crew is stored or prepared. Thus the first human case on board a vessel is often some member of the crew whose duties take him into the food store. The storekeeper or the saloon steward who carries the food from the galley to the
saloon is specially liable to infection, and the steward may in turn infect the captain and other officers upon whom he attends. It is therefore of importance that all food stores on board ship should be rendered ratproof. It appears probable that rats often gain access to ships by being carried on board with the cargo. They have sometimes been found in bales, bags, barrels, and crates containing a variety of different goods, such as grain, fruit, and yegetables, particularly when a cargo intended for a vessel has been left undisturbed for some time in dock warehouses. Before shipment such cargo should be carefully looked over. Above all, every means should be employed to prevent rats at a plague-infected port gaining access to a vessel which is to carry grain or other cargo to a distant country. It is probable that this precaution has not always been observed in the past.
TI’anspo1’t of Rats. As indicating the extent to which rats from
are
conveyed
to another through the agency of shipping Dr. Reece’s remarks on the change of the species of rats found at the English ports are very interesting. A hundred and fifty years ago the rat of this country was the Mus rattus, the black rat, or old English rat. When the brown rat, 31,us decumanus, came to Britain it practically exterminated the old English rat, and a few years ago it was hardly possible to obtain a specimen of the black rat. In recent years the rat population of this country has undergone a further change owing to the reintroduction from abroad of the black rat and the appearance of a third species, also black, known as the Mus alexandrinus. From returns received by the Ministry of Health it would appear that these two rats are increasing in number at certain ports. The number of brown rats destroyed at London and Cardiff far exceeds the number of black rats, whereas at Liverpool and Hull the two black rats predominate. The presence among ships’ rats of the species most prone to acquire, carry, and transmit the infection of plague is somewhat disquieting and demonstrates the desirability of destroying these rodents at the point at which this process may most effectively be carried out-namely, on board ship immediately after discharge of the cargo. one
country
Plagtw Prevention at Liverpool. The annual report for 1919 of the medical officer of health to the Port Sanitary Authority of Liverpool contains, in the section devoted to rats and plague, tables showing that over 20,000 rats were caught on ships and quays by the authority’s rat-catchers during the year, in addition to 50,000 disposed of by various shipping firms employing their own means of deratisaAn example of the new duties imposed on tion. port sanitary authorities by recent legislation is the Rats and Mice Destruction Act, 1919, which applies to a vessel as though it were land ; the master of a vessel is deemed to be the occupier thereof, thus becoming responsible for taking reasonable and practical steps to rid his property of rats and mice. The world-wide distribution of plague was maintained during the year, but one case only was landed at Liverpool out of a ship which had sailed from Bombay. In the port of Liverpool 310 rats were examined bacteriologically, and 20 of this number were found to be plague-infected; most of the latter could be traced to a single vessel. The following precautions were adopted. The vessel was breasted 6 feet off the quay, rat-guards were placed on all mooring-ropes, gangways were whitewashed and hoisted when not in use; extra labour was engaged, the cargo was searched for rats, the vessel also searched before, during, and after discharge of cargo ; the names and addresses of the crew were obtained and the men visited ; any dock labourer or carpenter absent from work on account of sickness was also visited; rat-catchers were kept continually at work on ship and quays; the matchboard lining and flooring of the lazaret were stripped and burnt, and the apartment thoroughly sprayed with kerosene; dead rats when found were immediately disinfected, and the whole vessel when empty was subjected to complete and simultaneous disinfection.
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